At the time of this study, interest in the genetic factors behind OCD was high, with some evidence from neuroimaging and animal studies  pointing to the role of genes affecting glutamate (one of the most important neurotransmitters linked to learning, memory, and mood) neurotransmission in the development of OCD. 

This study by Drs. Arnold and Kennedy, along with Drs. Peggy Richter, Tanya Murphy, and Wayne Goodman, studied whether there was an association between two glutamate system genes (GRIN2B and SLC1A1) and parts of the brain linked to OCD through neuroimaging and DNA genotyping in a sample of 31 children with OCD. The results showed that a variant of GRIN2B was associated with the left orbitofrontal cortex and right anterior cingulate cortex volume, and a variant of SLC1A1 was associated with increased total, left, and right thalamus volume. The study showed preliminary evidence of glutamate-related  gene markers that relate to the volume of brain regions in children with OCD.

Resulting Publication:

*Arnold, P.D., MacMaster, F.P., Hanna, G.L., Richter, M.A., Sicard, T., Burroughs, E., Mirza, Y., Easter, P.C., Rose, M., Kennedy, J.L., & Rosenberg, D.R. (2009). Glutamate system genes associated with ventral prefrontal and thalamic volume in pediatric obsessive-compulsive disorder. Brain Imaging and Behavior, 3(1), 64-76. doi:10.1007/s11682-008–9050-3